As computing devices are reduced in size, there is reduced available space for storage devices such as a hard disk drive or an I/O device. In order to expand a portable, laptop, or any other type of computer's capacity and functioning capability, manufacturers have devised “plug-in” peripheral cards in the form of printed circuit boards contained within an exterior casing. The Personal Computer Memory Card International Association (PCMCIA) and comparable organizations have established certain size and shape standards for the construction of the peripheral cards. These peripheral cards including associated casings are termed “PCMCIA” style peripheral devices.
The PCMCIA style devices can be used to perform the functions of software, resident memory in hardware devices, or as a hard drive. The devices can be used to facilitate LAN networking and wireless networking, as flash memory, as paging devices, and as FAX modems. They may be used in cellular telephones, PROMS, EPROMS, EEPROMS, RAMS, SRAMS, and DRAMS. The devices can be used in the form of IC cards or memory cards and as I/O cards for computer communication systems.
A conventional PCMCIA style device comprises a pair of metallic top and bottom covers configured to be engaged together, a supporting frame, a circuit board, with mounted electronic components, mounted on the frame, and primary and sometimes secondary electrical connectors. The primary connector is typically referred to as an “I/O” connector. The primary connector is provided on one end of the device for interfacing the memory card, and particularly the printed circuit board contained within the PCMCIA style device, to the outside device to which the PCMCIA style device is mated. The primary connector is designed to extract the contents of the memory stored on the printed circuit board and to bus data to and from an outside device, such as a computer or other electronic device. In this fashion, data traverses the interface between the PCMCIA style device and the outside device so that the data can be efficiently transferred and used by the outside device to which the PCMCIA style device is mated for its intended purpose. In one typical assembly, the circuit board is equipped with the primary and secondary connectors at opposite ends thereof and then attached to the supporting frame before being sandwiched between the top and bottom metallic covers.
At the present time, there are three different PCMCIA style device types, as defined by PCMCIA. The three PC card types are as follows:
a. Type I PC Cards are 54 mm by 85.6 mm, by 3.3 mm (0.130″) thick.
b. Type II PC Cards are 54 mm by 85.6 mm by 5 mm (0.195″) thick. The raised substrate areas of these cards are 48 mm in width.
c. Type III PC Cards are 54 mm by 85.6 mm with a substrate area thickness of 10.5 mm, and a card guide opening width requirement of 51 mm of the header connector to accommodate the slightly raised substrate area.
A new peripheral card named EXPRESS 34 has been proposed. In addition to the characteristics of the PCMCIA style device, the new peripheral card offers key advantages in terms of faster speed and smaller size. So, devices which connect the EXPRESS 34 and the PCI Express interfaces in notebook computers must have low profile interconnection and also meet the signal integrity requirement of PCI Express.
Examples of peripheral cards are described in U.S. Pat. Nos. 6,824,969; 5,397,857; 5,397,857; 6,004,144 and 6,474,998.
It is well known that electronic signals within electronic packages emit electromagnetic energy from the package, which causes electromagnetic interference (EMI) in other electric signals. It is desired to provide a complete and efficient shielding against the emission of EMI. On the other hand, electrostatic discharge (ESD) is also another important issue because electronic components are also very sensitive to ESD and special care must be taken in handling. Radio Frequency (RF) interference can also be a problem. However, if the package is properly shielded by a conductive material, it will serve to reduce EMI, RF and ESD problems.
FIG. 8 illustrates in section a prior art electronic device, in the form of a PCMCIA style device. When an electronic component 2 mounted on a card 3 must be shielded by a shield 4, the thickness of the shield 4 and any necessary vertical clearance between the shield 4 and a device cover 5 reduces valuable vertical usable space within the device. Additionally, the sidewalls of the shield 4 reduce lateral usable space within the device.
Given the strict thickness limitations of the aforementioned types of electronic devices, and given the desirability of fitting more components and more complex components into electronic devices, the present inventor has recognized the desirability of maximizing the usable inside volume of an electronic device by increasing the usable thickness of an electronic device for working components within the electronic device.